Abstract
Purpose :
Behçet's disease (BD) is a chronic systemic inflammatory disorder characterized by recurrent ocular symptoms, oral and genital ulcers, and skin lesions. The etiology of BD is still uncertain, but currently some external environmental factors are thought to trigger BD in individuals with a particular genetic background. It is well established that the human leukocyte antigen (HLA) class I allele, HLA-B*51, is strongly associated with BD in many different ethnic groups. In addition, another HLA class I allele, HLA-A*26, shows strong association with BD independently of HLA-B*51 in several ethnic populations. Both HLA alleles are reportedly involved in the development of ocular lesions in BD. The purpose of this study was to clarify the contribution of all HLA-A and HLA-B alleles to genetic predisposition in ocular BD with a large Japanese cohort.
Methods :
A total of 608 unrelated patients with BD (including 469 patients with ocular involvement) and 2,955 unrelated healthy controls, all of Japanese descent, were enrolled in this study. For the genotyping of the HLA-A and HLA-B alleles, we conducted HLA imputation using SNP2HLA with the genotypes of thousands of SNPs in the HLA region from our existing genome-wide association studies.
Results :
This study, as well as previous studies, found that HLA-B*51 and HLA-A*26 were significantly associated with increased risk of ocular lesions in BD. In addition, we newly identified three HLA class I alleles, HLA-B*61, HLA-B*70 and HLA-A*01, significantly associated with increased risk of ocular BD but not non-ocular BD. Moreover, we also identified four novel protective HLA class I alleles, HLA-B*44, HLA-B*54, HLA-A*11 and HLA-A*33, for ocular BD.
Conclusions :
In this study, we were able to identify new risk or protective HLA-A and HLA-B alleles for the development of ocular lesions in BD. To confirm the findings, future validation studies with other independent populations are needed.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.